P0164 Toxicity profiles of adjuvant docetaxel-cyclophosphamide in Asian compared with caucasian patients with breast cancer

Abstract

Background Ethnic differences in treatment-related toxicities exist between Eastern and Western patients. Our previous retrospective study has demonstrated racial differences in acute toxicities in patients receiving anthracycline-based chemotherapy. In this retrospective study, we aimed to compare the difference in tolerance to adjuvant docetaxel-cyclophosphamide (TC) between patients of different ethnicities. Methods Data were collected from six international breast cancer centres at which patients were planned for treatment with adjuvant TC (docetaxel 60–75 mg/m 2 and cyclophosphamide 600 mg/m 2 every 21 day for four cycles). Haematological toxicities were assessed by first episode of grade 2 or higher toxicity and disease-free survival was also evaluated. Findings From March 2004 to July 2013, 127 Asian patients (80 Chinese, 46 Japanese, and one Filipino) and 100 Caucasian patients were retrospectively compared for treatment-related toxicities. Baseline demographics and tumour characteristics were different between Asians and Caucasians. When compared to Caucasians, more Asians were premenopausal (61/126, 48.4% versus 30/95, 31.6%; p = 0.013) and less obese (6/127, 4.7% versus 21/100, 21.0%; p p p = 0.027). During the four cycles of chemotherapy, Asians had a significant higher rate of grade ⩾ 2 neutropenia than Caucasians (58/127, 45.7% versus 6/100, 6.0%; p p = 0.046) (table). Differences in grade ⩾ 3 neutropenia were also noted (39/127, 30.7% versus 4/100, 4.0%, p p = 0.764). Other hematological and non-hematological toxicities were much the same between the two ethnic groups. Of 205 patients eligible for survival analysis, 188 (91.7%) patients were disease-free and no significant difference in disease-free survival was observed between Asians and Caucasians at a median follow-up of 23 months. Interpretation Ethnic differences in toxicity profile were noted between Asian and Caucasian patients receiving TC, suggesting the possibility of different pharmcogenomics between ethnic groups. Further validation is essential to underpin differential treatment paradigms for various ethnic groups.